standard conversions:Qualification conversions

This is the point from ISO :Standard Conversions:Array-to-pointer conversion: $4.4: Qualification conversions /6th point

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standard conversions:Qualification conversions

     Two multi-level pointer to member types or two multi-level mixed pointer 
     and pointer to member types T1 and T2 are simil开发者_JAVA技巧ar if there exists a type T
     and integer n > 0 such that:

  T 1 is cv 1 , 0 P 0 to cv 1 , 1 P 1 to . . . cv 1 , n − 1 P n − 1 to cv 1 , n T
                             and
  T 2 is cv 2 , 0 P 0 to cv 2 , 1 P 1 to . . . cv 2 , n − 1 P n − 1 to cv 2 , n T

What it meant for? Please check the previous question also? Can any one Explain this.If possible give the example .. What actually meant for that form.Can any one eloborate if it is possible.

other question:

Why the standard is going for such form.Is there any reason fo this?

This rule is part of the rules that tell you whether there is a conversion from int*const* to int volatile**. You can see that they're similar, because they're both two levels of indirection away from int.

When converting between two similar types, you have to use the conversion rules for similar types. There are different rules when converting between two types that are not similar.